Yol. 62. ,] THE HIGHEST SILURIAN OF THE LUDLOW DISTRICT. 221 



EXPLANATION OF PLATE XXII. 



Geological map of the neighbourhood of Ludlow, on the scale of 

 2 inches to the mile. 



Discussion. 



The President said that he was glad to see that, shortly after a 

 paper had been read by one Cambridge student upon Sedgwick's 

 classical area, other Cambridge students had devoted attention to 

 the equally-classical region of Siluria. In each case, he understood 

 that the authors accepted the broad lines drawn by the earlier 

 workers, but gave more minute divisions than had been (in the former 

 ■state of our knowledge) possible. 



He congratulated the workers on the results that they had 

 obtained, by means of groups of fost Is which hitherto had not been 

 extensively used in the stratigraphical classification of the Lower 

 Palaeozoic rocks of Britain. H felt that the Authoresses had 

 established their classification for the region described. Whether 

 it was applicable to wider areas remained to be seen, and he hoped 

 that the Authoresses themselves would be able to establish this, 

 for they had proved themselves eminently qualified for the task. 



Prof. Hughes expressed his appreciation of the advantages which 

 the Society now enjoyed, of hearing the results of the excellent 

 work done by women in Geology from themselves and discussing 

 the conclusions arrived at with them. Turning then to the subject- 

 matter, he thought that the great interest of the paper lay in its 

 being a careful examination of the lithological and palaeontological 

 characters of the deposits which were laid down at the close of the 

 Silurian Period, when some great geographical changes were pending 

 which brought the Silurian conditions to an end, and with no 

 unconformity ushered in the Old Red Sandstone. This was quite 

 different from the conditions which were found to have prevailed 

 in North Wales and the North of England, where there was no Old 

 Eed of the Southern type, but the upturned edges of all the 

 Silurian to the highest beds there seen were cut oft: and covered 

 discordantly by the so-called ' Old Eed/ which he considered to be 

 the basement-bed of the Devonian or Carboniferous. 



In answer to a question put hj Dr. Teall, the speaker explained 

 what he meant by the Northern and Southern type of Old Eed, 

 by means of a diagram sketched on the blackboard. 



Mr. Hopeinson congratulated the Authoresses upon the excellent 

 stratigraphical and palaeontological work which their paper evinced. 

 He had always considered that the Monograptus-leintwardinensis 

 Beds formed the summit of the Lower Ludlow rocks, and had 

 recorded (in 1872) one species of graptolite only, of wide range 

 (Monograptus colonus), as occurring in the Aymestry Limestone, 

 having found it in shale between the two beds of this lime- 

 stone at Mock tree Quarry. If, as he understood, the Authoresses 

 carried down the line of division between the Lower Ludlow rocks 

 -and the Aymestry Limestone to below the fissile flagstones of 

 Q.J.G.S. No. 246. r 



